'whole home backup' confusion

[jgbaum]

I recently had a system installed (16kW, 2PW+, backup gateway 2) and all of my paperwork references 'whole home backup'. Basically, they pulled all of my loads from my main panel into a subpanel connected to the gateway. The only breaker in my main panel now is a 100A going to the gateway. What's odd to me is that they had me upgrade my main panel and service (which required significant trenching and $$$) from 100A to 200A, but they're only feeding this subpanel (which is capable of 225A) with 100A. There are several new loads I'd like to add in the coming months (EV chargers, electric dryer, water heater), which my project advisor was aware of, but there doesn't seem to be the bandwidth to support these in the subpanel. Am I mistaken? Should I ask Tesla to update the wiring/breaker to 200A?

My understanding (which may be wrong!) is that in order to be powered by my PV system or PWs when the grid is out, loads would need to be in the subpanel as no electricity would flow to the main.

I've included the wiring diagram below. Any insight would be much appreciated.

Thanks!

 

[wwhitney]

So now the issue is that if your house gas piping becomes your only grounding electrode, the current will try to through the gas meter from the new ground clamp.

Nice write up above. But any current that flows on the grounding electrode system will always flow on all grounding electrodes, in inverse proportion to their impedances. That is, current takes all paths, not just the path of lowest impedance.

is it true that the current NEC doesn't require a ground rod if an Ufer ground is used?

The NEC requires that all grounding electrodes present be bonded together to become the grounding electrode system, and that you must provide at least one grounding electrode. Also, a water pipe electrode does not suffice as the only electrode; it requires a supplementary electrode. And lastly, a single ground rod alone does not suffice as the only electrode, or as the only electrode supplementary to a water pipe electrode, you need a 2nd ground rod. [Unless you prove it has a resistance to ground of 25 ohms or less, an arbitrary threshold that is hard to hit, and even if you do, measuring grounding electrode resistance properly is more trouble than driving a 2nd ground rod.]

So yes, if you have a Concrete Encased Electrode (CEE or Ufer), you don't need to drive any ground rods to supplement it, but you still need to bond any existing ground rods, as well connect to any underground metal water pipe.

So where am I supposed to form this dielectric union? Like do I need to find another way to get to the as line other than this stuff sticking out of the ground?

PG&E has a dielectric union installed on one side of their meter (probably line side, not sure). And they maintain ownership of the meter, the outlet (usually offset) nipple, and the first tee (service tee) that should have a plug facing out away from the building. Your ownership starts at the outlet of the service tee that faces the house. So you can move your bonding connection from the gas riser to the house side of the service tee and all will be well.

Cheers, Wayne

 

[holeydonut]

PG&E has a dielectric union installed on one side of their meter (probably line side, not sure). And they maintain ownership of the meter, the outlet (usually offset) nipple, and the first tee (service tee) that should have a plug facing out away from the building. Your ownership starts at the outlet of the service tee that faces the house. So you can move your bonding connection from the gas riser to the house side of the service tee and all will be well.

Cheers, Wayne

Since I have no UFERs and no common sense... can you confirm what I think you're saying?

It sounds like I can move the clamps from where they currently are and shift them to right next to my house (but still on the outside of the house)? The diagram from PG&E's letter seems to indicate the smaller circle below is still in the "cannot use" zone though.

Edit, here's the language that basically says even on the "house side" I can't bond there since I'd be within 36" of that precious riser. Which still leaves me with the confusing problem that I have no clue where to bond these grounding thingies to the gas line.

 

[BGbreeder]

I'm super confused now... because earlier in this thread it seems like there was agreement where somehow connecting my grounding rods to the natural gas riser and water line was supposed to be some dielectric union. That seemed to correlate with what the Contra Costa County inspector was trying to say when he made Sunrun add some extra leads/clamps connecting my grounding rods to this gas riser.

But then PG&E is telling me I cannot affix any of these clamps on their natural gas equipment.

So where am I supposed to form this dielectric union? Like do I need to find another way to get to the underground gas pipe other than this stuff sticking out of the ground? Like where would I go to be 36" from the riser but still accomplish what the County inspector wanted?

I don't understand what the CCC inspector was trying for. Trying to ground solar at a gas line, or trying to ground a gas line at a meter/regulator seems...hard to comprehend.

That said, gas lines my understanding of normal practice is that the gas line is normally bonded at the appliance it serves (I.e. the hot water heater), and usually grounded. My understanding was hot water line bonded to cold water line, bonded to he gas line, and then run back to the house ground, (some AHJ require 8ga, some allow smaller, apparently) but in poking around, the ground run back to the house ground seems to have some variance by jurisdiction. In general, it is not a good practice to have grounds at multiple locations on a pipe to minimize ground loops (currents) that cause corrosion. If you have a plastic line feeding your meter, then your gas line isn't grounded, unless you have a ground from your gas line elsewhere.

I think PG&E will be happy if you move gas line ground clamp more than 36" away from the meter.

Does that help?

All the best,

BG

 

[holeydonut]

Also @bmah and @jboy210, can you show me how your 8' grounding electrodes and bonding with your gas piping was done on your systems? You both are in Contra Costa County (I think? Or maybe you're in Almeda county? barf.) and presumably have have some bonding that passes both the county and PG&E's requirements.

 

[holeydonut]

I think PG&E will be happy if you move gas line ground clamp more than 36" away from the meter.

Where could I accomplish this? You're saying I can bond at the hot water heater or some gas metal gas pipe that is inside my house?

The inspector insisted all this bonding crap had to be outdoors though, so I'm clueless how I could ever get 36" from the riser and still be outdoors.

 

[BGbreeder]

Since I have no UFERs and no common sense... can you confirm what I think you're saying?

It sounds like I can move the clamps from where they currently are and shift them to right next to my house (but still on the outside of the house)? The diagram from PG&E's letter seems to indicate the smaller circle below is still in the "cannot use" zone though.

View attachment 961301

Edit, here's the language that basically says even on the "house side" I can't bond there since I'd be within 36" of that precious riser. Which still leaves me with the confusing problem that I have no clue where to bond these grounding thingies to the gas line.

View attachment 961304

Somewhere farther back on the gas line, like 36" away, through the wall, though I don't know how PG&E treats walls for distance gas line grounds....If you can run a ground across the hot water heater pipes to the gas line and back out to the solar grounds, you should be in good shape, but the other side of the wall might suffice for CCC. I don't know. I think the intent is to keep grounding arcs away from sources of gas (the meter area) while ensuring the gas lines aren't sources of ignition elsewhere due to voltage differences.

All the best,

BG

 

[holeydonut]

Somewhere farther back on the gas line, like 36" away, through the wall, though I don't know how PG&E treats walls for distance gas line grounds....

Ok so if I just ignore what the original County inspector said; then we can just bond indoors like what Sunrun originally had. And PG&E wouldn't see the bond next to their bloody riser and everybody is happy-happy. And hopefully the house doesn't burn down or corrode too fast.

Edit: Any chance you can post a picture of what your "dielectric union" bonding across 2 electrodes and your gas pipe looks like?

 

[wwhitney]

Edit: Any chance you can post a picture of what your "dielectric union" bonding across 2 electrodes and your gas pipe looks like?

A "dielectric union" is the opposite of a bond, it's a connection for gas or water that avoids electrical continuity while still letting gas or water pass through.

A gas meter has a dielectric union so that the building gas piping is not connected electrically to any of the gas piping in the ground. Because the building gas piping should be bonded, but they don't want the underground gas piping bonded.

A water heater often has dielectric unions on its input/output, because the tank is made of steel, and the water pipe connections may be copper, and a copper/steel connection will cause the steel to corrode. So because the water heater often has dielectric unions, if your cold water pipe is already bonded via its use as a grounding electrode, that bond may not carry over to the hot water pipe. Therefore an explicit hot water-cold water bond is often called for at the water heater.

The NEC doesn't require any gas pipe bond beyond the EGC of the gas-using fixture. However, it is common practice at least in the Bay Area (and maybe the LA area as well) for inspectors to look for a hot-cold-gas bond at a gas water heater. They shouldn't really fail you if you choose to do the bonding in other ways, but it would at least raise eyebrows, and it's a sufficiently reasonable idea that it's just best to do that.

So what that literally means is 3 grounding clamps, like the one that is improperly installed on your gas riser, attached to the gas iron pipe, the copper cold water pipe, and the copper hot water pipe, all near the water heater, and a suitable sized bare copper wire strung through the 3 bonding lugs on the 3 grounding clamps. Suitably sized depends on your service conductor size; if your biggest breaker is labeled 200A then most likely a #4 solid copper would suffice.

Cheers, Wayne

 

[bmah]

Also @bmah and @jboy210, can you show me how your 8' grounding electrodes and bonding with your gas piping was done on your systems? You both are in Contra Costa County (I think? Or maybe you're in Almeda county? barf.) and presumably have have some bonding that passes both the county and PG&E's requirements.

Sorry, I'm not following this thread so I have almost no context. I tried reading the last two pages and I'm getting dizzy.

I'm in Contra Costa County. I know nothing about "bonding with [my] gas piping". My natural gas riser is on the other end of the house from where my inverter, Powerwalls, and electric meters are.

There is a grounding rod close by to where the aforementioned equipment is. The solar installers (Solar City in 2010) mentioned looking for it and they were very surprised that I knew where it was. I don't know what they bonded (if anything) to it or how. I don't think this subject came up when we had the Powerwalls installed, by Tesla, in 2019.

Neither Contra Costa County nor PG&E had any concerns related to bonding or grounds. Note that I gave the years for my installs above. It might be that some inspector has different requirements / interpretations in 2023 than they did in 2010 or 2019.

Sorry I can't be of more help. Ignorance is bliss.

Bruce.

 

[Vines]

Lol my feeble brain is literally unable to comprehend half of what you posted.

So if that bonding clamp is relocated (see picture below) then everything is ok? Or does this bonding clamp need to be completely removed?

I have two 8' grounding electrodes (they just don't appear in the picture). They are about 5' apart. One of these has the hot water heater connected to it via a long run of copper. And the other grounding rod is connected to some leads comes off the TEG gateway and my MSP. Sunrun neutral-bonded-to-ground on both my TEG2 and MSP... then just connected that common ground to one of those 8' rods.

But both of these rods are then spliced into the gas riser per my pic.

@BGbreeder that little hook-thing wire attached to the riser is a tracer wire. It's supposed to help people know where the actual gas pipe is so they don't spike one of those 8' grounding rods through my gas line I guess lol.

View attachment 961292

I know it's complicated and here's what I would have an electrician do if I were you:

1. Relocate the ground clamp to be somewhere on your side of the gas piping and also 36" from the gas meter as required. Connect that ground clamp to the same bonding wire that the hot and cold water are connected to, and this wire terminates at the ground bus of the msp.

2. You should have only one connection from your home to the grounding electrode system, and the grounding electrodes should all be bonded together.

So bond the one new ground rod to the other ground rod and nothing else except ground rods, pipes or other electrodes in the dirt. Connect the service to the other ground rod at one location only, this is the GEC. Connect the ground wire (EGC) from your TEG to the MSP equipment ground bar instead of the ground rod.

 

[holeydonut]

I know it's complicated and here's what I would have an electrician do if I were you:

1. Relocate the ground clamp to be somewhere on your side of the gas piping and also 36" from the gas meter as required. Connect that ground clamp to the same bonding wire that the hot and cold water are connected to, and this wire terminates at the ground bus of the msp.

2. You should have only one connection from your home to the grounding electrode system, and the grounding electrodes should all be bonded together.

So bond the one new ground rod to the other ground rod and nothing else except ground rods, pipes or other electrodes in the dirt. Connect the service to the other ground rod at one location only, this is the GEC. Connect the ground wire (EGC) from your TEG to the MSP equipment ground bar instead of the ground rod.

Thanks Vines, much appreciate your simpler explanation for simpler minds as my own.

Would you ignore the Contra Costa County Inspector's requirement where the bonding to "home's side of the gas piping" has to be outside? That's basically my hang-up. I can't figure out how to satisfy everybody's requirements since they seem to conflict.

 

[wwhitney]

Would you ignore the Contra Costa County Inspector's requirement where the bonding to "home's side of the gas piping" has to be outside? That's basically my hang-up.

There is no such requirement in the adopted codes; the inspector made it up.

Cheers, Wayne

 

[holeydonut]

Sorry, I'm not following this thread so I have almost no context. I tried reading the last two pages and I'm getting dizzy.

I'm in Contra Costa County. I know nothing about "bonding with [my] gas piping". My natural gas riser is on the other end of the house from where my inverter, Powerwalls, and electric meters are.

There is a grounding rod close by to where the aforementioned equipment is. The solar installers (Solar City in 2010) mentioned looking for it and they were very surprised that I knew where it was. I don't know what they bonded (if anything) to it or how. I don't think this subject came up when we had the Powerwalls installed, by Tesla, in 2019.

Neither Contra Costa County nor PG&E had any concerns related to bonding or grounds. Note that I gave the years for my installs above. It might be that some inspector has different requirements / interpretations in 2023 than they did in 2010 or 2019.

Sorry I can't be of more help. Ignorance is bliss.

Bruce.

The only context you need is for some reason PG&E and Contra Costa County seem to be using my house as a model home of "violations" to pursue the most asinine interpretation of their rules and watch me try and figure things out. If not for TMC there would be 0% chance I'd have solar or Powerwalls because I am stupid and incapable of figuring out this stuff on my own. Searching about these topics literally brings up the posts in this forum. That Mike Holt forum or other Solar-Forums don't even talk about this stuff.

I'm sure both of these huge mega organizations are monitoring my activity in this forum and get a nice giggle out of it. All because some dumb-azz T-Man thought solar and ESS hurt his pension I guess?

Here is a quick list of things that I've somehow had to deal with that I don't think any other person on this forum has had to individually deal with.

1) Asserting a main service panel like-for-like exemption to the 36" rule for swaps 200A for 200A is disallowed for solar/ESS installs since this would hurt PG&E employee pensions

2) Disconnect-frenzy and PG&E telling me they were going to enforce 060559 no matter what it actually says in the document.

3) PG&E interconnections team claiming that the PG&E Diablo Planning Department didn't actually know what type of service entry I had and... so they required a separate PG&E QEW to drive out and put eyes on my service entry conductors.

4) Not accepting Tesla Gateway/Powerwall PCS certifications even though they're literally published by the California Energy Commission; and disagreeing with how the 120% percent rule could be applied which would de-rate my house service to 125A

5) Identifying I am missing weep holes on a LB and a bottom LB for an external EMT run

6) Identifying my condensing unit of my air conditioner is too close to my solar and too close to my fence... which required me to install a new gate on the other side of my house

7) Questioning whether or not Sunrun had actually installed batteries on my wall so they sent someone from AESC to visit my home and take redundant pictures that a PG&E QEW had taken a few weeks prior

8) Grounding rods. Who knew? ( other than @wwhitney @BGbreeder and @Vines edit: and @miimura ).

 

[yblaser]

Interesting discussion. I have a somewhat related grounding issue which I would appreciate some input on.

Prior to moving into our house I had the service upgraded to 200A and a new MSP installed. There is a single ground wire that goes from my MSP to two new grounding rods and then is connected to the riser of a hose bib in my front yard. They also bonded the hot, cold and gas line at the hot water heater.

What I didn't notice until after the work was completed and inspected was that the riser of the hose bib which from afar looked like corroded galvanized steel pipe was really just a dirty grey plastic riser. When I got solar installed I did point it out to the Tesla site assesor when he was looking at the grounding, but he just shrugged.

Obviously this is not to code, but I am wondering what real world problems this might cause? There is no metal pipes nearby the grounding rods that I can connect the ground to. Can the ground to the water pipe be a separate run from the MSP or from a subpanel?

 

[wwhitney]

Obviously this is not to code, but I am wondering what real world problems this might cause? There is no metal pipes nearby the grounding rods that I can connect the ground to. Can the ground to the water pipe be a separate run from the MSP or from a subpanel?

If you have a metal water pipe that is underground for at least 10', and if it is continuous to inside the house, then you need to use it as an electrode by bonding to it outside or within 5' of its entering the house. [If the metal portion doesn't extend inside, it's a little ambiguous whether you need to use it, but you certainly could use it by connecting to the metal portion outside.] This electrode bonding jumper can be a separate GEC from the service panel.

If you don't have such an electrode, but you still have a metal water piping system inside, then you need to bond it anywhere along its length. This bonding jumper can originate at any panel.

Cheers, Wayne

 

[jjrandorin]

Exhibit W on why I am the dumbest-ass-MF-er on TMC. @jjrandorin, can I change my forum username to DAMF? Or is that considered profanity?

Assuming this is an actual question and not ment to be sarcasm, if you changed your username to that combination of letters, and more importantly, didnt spell out what they mean to you in posts, no one would probably think twice about it because its not obvious what that combination of letters means.

Or, in other words, dont say what you said after the word "why", up to the period, in the sentence above.

 

[Vines]

Thanks Vines, much appreciate your simpler explanation for simpler minds as my own.

Would you ignore the Contra Costa County Inspector's requirement where the bonding to "home's side of the gas piping" has to be outside? That's basically my hang-up. I can't figure out how to satisfy everybody's requirements since they seem to conflict.

Yes, I would ignore that requirement, or just tell him to his face that PGE doesn't allow this. Then he'd probably shrug.

 

[holeydonut]

Yes, I would ignore that requirement, or just tell him to his face that PGE doesn't allow this. Then he'd probably shrug.

Lucky for CoCoCo folks, that particular inspector seems to have retired in 2021.

 

[zƬesla]

Assuming this is an actual question and not ment to be sarcasm, if you changed your username to that combination of letters, and more importantly, didnt spell out what they mean to you in posts, no one would probably think twice about it because its not obvious what that combination of letters means.

Or, in other words, dont say what you said after the word "why", up to the period, in the sentence above.

Just get it as a license plate then make it your profile photo

 

[holeydonut]

Yes, I would ignore that requirement, or just tell him to his face that PGE doesn't allow this. Then he'd probably shrug.

FYI @Vines - just because you will enjoy hearing about how other solar companies c*ck things up...

Sunrun finally came out to do the repair and remove the grounding from the gas riser. The tech shows up, and says to me "the work order says there's an issue with the install". I walked him over to the gas riser and pointed at the bonding on the riser and handed him the PG&E notice indicating the bonding to the riser violates whatever Greenbook thing says no bonding to risers. I told him I was asking Sunrun to repair this since Sunrun did the bonding to the riser.

The guy says "ok...". I looked at him and said "that was the least assuring OK I've heard in a long time. if you have any questions please knock on my door so we can discuss."

5 minutes later he's driving away without punching out or doing a goddamn thing. I get a call from Sunrun dispatch saying since the solar system was generating electricity the tech didn't know what else to do.

I waited 2 goddamn months for this. Bullshit.